<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      display: flex;
      width: 600px;
      height: 100px;
      background-color: lawngreen;
      margin: 50px auto;
      justify-content: center;
      align-items: center;
    }
   div .insert {
    width: 50px;
    height: 50%;
    background-color: red;
    font-size: 24px;
    font-weight: 1000;
    }
  </style>
</head>
<body>
  <div>
    <div class="insert">棒</div>
  </div>
</body>
</html>